In horticulture given the height of many crop plants irrigation systems tend to be:                In situ systems which are fixed in place e.g. buried pipes or plumbed systems used in hot houses;        High pressure systems using long reaching water jets;        Expensive pivot irrigators which again tend to suffer from being difficult to transport between fields on a regular basis.        
There thus exists in horticultural or horticulture a real need for a mobile irrigation system which can operate on low pressure, such as mains pressure, which can spread fluid over crop plants situated one or more plants away from the sprinkler.
Such systems are either fixed in place, or require a major amount of labour, large vehicles or other equipment in order to move the system from one paddock to another, or to another part of the same paddock.
This lack of portability, together with the initial setup costs, contributes to a higher capital cost to the user.
These large irrigation systems also have a further disadvantage of being difficult to manoeuver into the required position on horticultural land such as orchards where movement is restricted by the trees.
Furthermore, these large irrigation systems also operate under high pressure which can easily damage the vegetation of the trees.
Therefore, small above ground irrigation systems with low-volume, low-pressure sprinkler heads are also known which provide improved portability. For example, New Zealand Patent No. 510282 discloses a sprinkler apparatus which comprises a housing to substantially protect a sprinkler unit mounted in the housing from damage, yet at the same time allows at least a portion of the sprinkler head to protrude above at least part of the upper edge of the housing. This type of sprinkler apparatus is commonly used in agriculture for farmed animals such as sheep, cattle, goats or deer and allows animals to continue to graze a paddock that has been irrigated using this type of low-pressure sprinkler system. Therefore, the sprinkler housing provides some form of protection to protect the sprinkler unit from damage.
New Zealand Patent No. 532441 discloses another low-pressure sprinkler apparatus which includes a housing and a strut. The strut extends from one side of the wall portion of the housing, above and over any moving parts of the sprinkler, and down to the opposite side of the wall portion of the housing. The purpose of the strut is to further prevent damage of the sprinkler unit by animals which may inadvertently kick or step onto or into the sprinkler apparatus.
However, a disadvantage of the above sprinkler apparatus is that the sprinkler head is mounted low and substantially within the housing of the sprinkler apparatus for protection. This type of configuration, although it provides protection from animals, it is particularly unsuitable for use in horticultural situations. This is because the sprinkler is located too low relative to the height of most crop plants to deliver fluid effectively. As the fluid only tends to reach plants directly adjacent to the sprinkler affecting the reach of the sprinkler and as a result not watering neighbouring plants which have plants between them and a sprinkler. Where for example, the sprinkler needs to deliver water to canopies or the tops of bushes that need to be irrigated.
As the sprinkler head is mounted low, it is not able to distribute fluid sufficiently far enough to provide the necessary irrigation to the canopy layer of trees, vines or the tops of other crop plants.
An object of the present invention, is to provide a sprinkler apparatus which overcomes the disadvantages of irrigation apparatus described above.
It is a further object of the present invention to at least provide the public with a useful choice.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
Throughout this specification, the word “comprise”, or variations thereof such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.